All modules are built statically. So we must generate a table with the
enty point to vlc can use them.

(patch) Fix _POSIX_CLOCK_SELECTION in emscripten (set value to 0) because clock_nanosleep is not defined.

transfert the canvas easier.

Configure is done with more option to disable some not needed features,
and enable some other needed features. Add some contribs to the built contribs.
The script will now compile vlc.

The toolchain is now on the incoming branch and on release mode, which is the most up to
date. Fix some typo in the checks and paths to see if emscripten is well
installed. The contribs are compiled for the good host.